1. Field of the Invention
The present invention relates to fuel cell systems, and an injection nozzle assembly for the fuel cell system.
2. Discussion of Related Art
To solve environmental or lack of natural resources problems, much attention has been paid to a fuel cell that electrochemically reacts oxygen in air with hydrogen obtained from hydro-carbonaceous fuel such as natural gas or the like, or from hydrogen-containing fuel such as methanol or the like, thereby generating electricity. Such fuel cell is classified into a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), a solid oxide fuel cell (SOFC), a polymer electrolyte membrane fuel cell (PEMFC), an alkaline fuel cell (AFC), etc. according to the electrolyte used. These fuel cells may be applied to various fields such as a mobile device, transportation, a distributed power source, etc. according to a kind of fuel, a driving temperature, an output range, etc.
Among these fuel cells, the PEMFC is beneficial because it has excellent output performance, low operation temperature, and quick start and response. The PEMFC includes a stack in which a plurality of unit cells generating electricity based on a chemical reaction between hydrogen gas and oxygen gas are stacked and a reformer supplying hydrogen gas obtained by reforming hydrogen-containing fuel including a hydro-carbonaceous material such as methanol, ethanol or natural gas to the stack. The PEMFC also includes a fuel feeder for feeding the reformer with the hydrogen-containing fuel by a pumping operation and an air supplier for supplying air to the stack.
A direct methanol fuel cell (DMFC) has been developed that uses hydrogen-containing fuel directly to generate electricity without employing the reformer for obtaining hydrogen gas. The DMFC has advantages in that operation temperature is low, response time is short, and the size thereof is small. Therefore, the DMFC has been actively researched. The DMFC includes a stack in which a plurality of unit cells generating electricity based on an electrochemical reaction between hydrogen gas and oxygen gas are stacked. The DMFC also includes a fuel feeder for feeding the stack with hydrogen-containing fuel by a pumping operation; and an air supplier for supplying air to the stack.
In a conventional DMFC, the pumping operation is essential to supply hydrogen-containing fuel to the stack. However, the pumping operation causes noise, vibration and much power consumption. In particular, the DMFC has low transformation efficiency for obtaining hydrogen from the supplied hydrogen-containing fuel.